The maintenance of transparency and deturgescence in the frog cornea is related to the rate of active transepithelial Cl transport. This transport process is supported by metabolic energy derived from the reactions of glycolysis and respiration. Therefore, metabolism and active transepithelial Cl transport are coupled; however, the mechanism of their coupling is not understood. This proposal has two objectives: namely, to obtain information pertinent for resolving how these processes are coupled and, secondly, to quantitate the efficiency of energy utilization by the Cl translocation mechanism. In isolated frog corneas, electrophysiological and metabolic parameters will be measured as functions of bathing solution composition and rate of active Cl transport. Electrophysiological methods include simultaneous measurement of transepithelial and intracellular epithelial concentrations of adenine nucleotides and inorganic phosphate in addition to the measurement of oxygen consumption. The objective of these approaches is to see whether there is a correlation between changes in the electrophysiological and metabolic parameters which result from altering either bathing solution composition or from selectively perturbing the rate of active transepithelial Cl transport. The results of these studies will provide a deeper insight into regulatory factors which control metabolic rate and in turn how metabolic rates are modulated by changes in the rate of active transepithelial Cl transport. With these approaches, it is also anticipated that the efficiency of energy utilization by the Cl pump can be quantitated.